Fuel injection pump



March 23, 1948. R. H. SHEPPARD FUEL INJECTION PUMP Filed Feb. 6, 1942 Patented 23; 1948 I .z,43s,19o V UNITED STATES PATENT oFFlcE Richard H. Sheppard, Hanover, Pa. Application February a, 1942, Serial No. 429,825

16 Claims. (Cl. 103-41) This invention relates to fuel injection pumps for Diesel type engines and has for its general object the simplification oi the design of such pumps. 7 Y

A particular object of the invention is to provide a pump which may be assembled and disassembled quickly and easily and in which the parts may be interchanged easily and with a minimum expenditure of time.

An important object of the present invention is the provision of means for the equalizing or the balancing of the several pumps without the need for removing any pump from the assembly, the adjustments being made by a slight rotation of an equalizing nut which moves the pump body toward and away from the plunger, which latter is' reciprocated by means of an adjustable cam on the engine shaft. By means of this mechanism extremely accurate delivery of fuel may be made since with an adjustment range of less than a thousandth of an inch in the relative height of the pump a correction may :be made which amounts to double the maximum error which may be expected in the amount of oil delivered by the particular pump which is being adjusted.

An important object of the invention lies in the details of construction of the adjusting wing of the equalizing screws the side surface of which is of a shape whereby thecenter lines of the set screws which holds the wing screw in place will always be substantially at right angles to the points at which the set screws contact the side surfaces of the wing of the adjusting screw.

In the drawings:

Figure 1 is an elevation of the assembly partly in central section.

Figure 2 is a horizontal section taken through the center of the wing section of the equalizing screw.

Figure 3 is a plan view but showing the pump in section.

Figure 4 is a vertical section on a larger scale through the equalizing screw.

Referring to Figure 1, the pump casing I0 is provided with a main cover or head l2 carrying a plurality of pump cylinders it which have a rhomboidal flange I 5 by means of which the pumps are secured to the casing and cover by means of bolts it having heads l1, one preferably proximate each of the narrower angle corners of the flanges l6.

The lower portion of the pump cylinder is a body 18 fitting rather snugly the equalizing screw 20 and extending an appreciable distance below the cover l2 into the spring chamber or cylinder V 2 chamber l9. Within the pump is a plunger 2i which rests upon and is moved by a cup-shaped cam rider 23 fitting a bore 22 in the casing in and driven by an adjustable cam 24, the-operation of which is explained fully in my co-pending appli.-'- cation S. N. 233,640, now Patent No. 2,276,630, issued March 17, 1942, of which the present application is a continuation in part.

The plunger 2| carries near its bottom a spring seat 26 held in place by a washer 21 and confining the spring 28 which at all timesurges the pump plunger 2| into contact with the cam rider and likewise holds the cam rider in contact with its operating cam 24, driven by the sleeve 25 in the cam chamber 29 of the casing l0. As will be seen from the above the plunger 2i with -a definite position of its cam 24 has a' fixed upper limit at any chosen setting of the several cams so that if the pump body is raised or lowered, the relation of pump cylinder and plunger will be altered and the amount of discharge may be adjusted to equalize the several pumps. Adjustment of all pumps together is made by the'mechanism illustrated and claimed in my said patent, including the longitudinally adjustable shaft 30 within the sleeve 25.

no pumping action takes place until the intake port 3i is completely covered. Asa result of this construction when the pump body is elevated with respect to the cover and the casing. the inlet port 3| remains open for a longer time and the pump therefore delivers less fuel to the engine cylinder or combustion chamber. Similarly, it the pump cylinder is lowered'toward the axis of the cam equalizing nut 20 has a threaded engagement as at 36 with a tapped hole in the cover whereby the screw when rotated moves axially with respect to the cover. The'fiat. top, generally circular, surface 38 of the adjusting screw 20 engages the bottom surface of the pump body flange 'l5. I prefer totuse a relatively'thick Duprene gasket between the pump body flange and the pump casing cover to keep out dust.

As best seen in Figure 2, the two wings of the equalizing screw 20 form a figure in plan roughly resembling the outline of the numeral 8. The tail portion 39 of the nut wing is bounded by sides 40 which are conveniently made at an angle of 19 to the long center line of the nut, although obviously this angle is not critical. The second or operating wing ll of the equalizing screw has a major arcuate outer surface 42 having a loose fit with the well 33 and its side or operating surface 44 is curved in such fashion that the center line 45 of the set screw 46 will always be at right angles to the point at which the set screw 48 contacts the operating surface 44. In practice I find that the major portion of this curve can well be an are. With the center line of the set screw at the preferred 60 angle, the radius of curvature of the surface 44 will be about three-eighths of an inch where the equalizing screw well 33 is a bit less than two inches in diameter.

In previous devices of this type the pumps have been balanced by means of a slight extension nut screwed over the end of the pump plunger. Theoretically the over-all length of the plunger could manufacturing tolerances were never the same.

With the present arrangement the pumps may be equalized in a short period of time. This is done simply as follows: The two bolts I! for each pump plunger are first loosened. One of the set screws 46 is then backed off a slight amount while the other or companion set screw is advanced. The amount of needed adjustment is extremely small and I have found that a total movement of rotation of the equalizing screw of as little as 70 is ample for all purposes for, in actual practice the equalizing screw need move axially a distance of only half a thousandth of an inch. When the set screws 46 have been properly positioned for the newly adjusted setting of the equalizing screw 20 the hold-down bolts l6 are tightened time looking the pump bodies to the pump casing V I 0.

An important feature of the present invention is the fact that the entire pump with its spring seat and plunger can be removed from the engine without movement of any other pump. The threaded opening in the cover is of such diameter as topermit the ready withdrawal of the spring seat 28, leaving only the cup-shape cam rider 23 in place resting lightly on its cam. The cam rider in turn may readily be removed after the other portions of the pump have been taken out by the mere expedient of removing the usual screw 49 which prevents rotation of the cam rider cup.

What I claim is:

1. In a Diesel engine of the type in which the plungers of the fuel injection pump are reciprocated by means of adjustable cams on a driving shaft, and no pumping action takes place until the intake fuel port is completely covered, 9. casing in which said shaft rotates about a fixed axis, a cylinder block assembly including a cover removably secured to the casing, a plurality of cylinder bodies individually supported by the cover and projecting through the cover into the casing for varying distances, means for moving each cylinder body a minute amount with respect to the 4 a cover and at right angles to the axis of said shaft, and means for locking each cylinder to the cover in such adjustedposition, whereby any one of the cylinder bodies may be released for readjustment -without disturbing any of the other cylinder bodies, and the adjustment is made without altering the position of the plungers orthe cams.

2. In 9, Diesel engine of the type in which the ing the cylinders in their adjusted positions.

3. In a fuel pump for a Diesel engine of the type in which the piston does not deliver fuel to the engine until after the piston has cut of! the by-pass port, a casing, a plunger operating means within the casing, a cover for said casing, a plurality of pump cylinders mounted on the cover in position to receive said plungers, and means for axially moving any one pump cylinder with respect to said casing without moving any of the other cylinders, and means for locking the cylinders in such adjusted positions.

4. The combination of claim 3 in which the first means includes a hollow sleeve surrounding a portion of the pump cylinder. 5. In a fuel pump for a type in whichthe plungers. do not pump fuel until the by-pass port is completely covered, a base, a

I equalizer member rotatable about the axis of the cylinder bearing against said cylinder and having a threaded connection with said base, and means for locking said equalizer member in rotated adjustment.

'7. In a fuel pump for 2. Diesel engine, a pump h'ead having therein a plurality of circular wells to receive fuel pump bodies and having a threaded opening axially of each well and merging therewith to accommodate cooperatively threaded nuts engaging the respective bodies to adjust axially said pump bodies in the wells, whereby the several bodies may independently be adjusted with respect to the pump head to aflect balancing of the several pumps.

8. In a hollow adjusting screw for fuel pump cylinders, a wing extending from said screw, a plurality of round tipped set screws adjustable to make contact with the operating surface of said wing, characterized in that the shape of said surface is such as to be normal to the engaging ends of the screws throughout a range of adjustment of the adjusting screw, whereby the thrust is directed in line of the set screw axis.

9. In 9. Diesel engine of the type in which'th'e fuel oil pumps are driven from the engine in such manner that the strokes of the several pump plungers are regulated in accordance with the load carried or the speed of the engine or both: a device for-balancing the several fuel oil pumps 0! Diesel engine of the the engine, comprising a base, a plurality oi pump cylinders, means for securing the cylinders to the base in fixed positions, equalizing nuts having a threaded engagement with the base and a planesuriace to plane-surface engagement with the proximate pump cylinder, a win extension on each nut, and a pair of opposing screws engaging eachwing extension to lock it in an angularly addusted position of the nut, whereby when the se curing means and one of the screws are loosened, the other screw of that assembly maybe rotated to elevate or to lower that pump cylinder with respect to the base, without disturbing the other pump cylinders, and such adjustment may be maintained by then moving the firstscrew and the securing means to tight engagement.

iii. The device of claim 9 in which the two screws are at an obtuse angle with respect to each other, and the side surfaces of the wing extensions of the nuts are roughly normal to the axes of the screws thru the major portion of the Y adjusting range.

ii. In combination, a support having a threaded opening, a member having threaded engagement with said opening so that rotation of the member will cause axial movement for adjustment of the member with respect to the support, a wing extending from the member, and a pinrality of means movable in the support and engaging the wing to loci; the member in adjusted position.

12. The device of claim 11 in which the wine is integral with the member, the member is a nut, and the means are two threaded bolts, whereby when one boltis loosened, the other bolt may turn the nut about its axis by extremely small amounts and when the nut is exactly positioned in this manner, it may be locked in place by tightening said one bolt.

13. The device oi claim 11 in which the member is a nut having a central opening to receive snugly a pump body, and means are provided for binding the pump body to the support and against the adjusted nut when the nut is locked in position.

14. In combination, a threaded member, an integral wing extending'from the member and having two spaced curved surfaces, :2 pair of opposed threaded positioning elements each engaging one of the curved surfaces, one element forcing the wing in one direction to raise the member and the other element forcing the wing in opposite direction to lower the member.

15. The device of claim 14 in which the curved surfaces are each so shaped that the surfaces are normal to the element in different adjusted positions,

16. In a device for locking, a body which moves about an axis, asupport, a body rotatable in said support, a plurality of-positioning elements rotatable in the support with their axes forming an obtuse angle, and an extension carried by the body to be engaged by both of said elements, the shape of the extension where engaged by theelements being such that the surface is at right angles to the axis of the proximate element thruout a range of movement of the body about its axis.

RICHARD H. SHEPPARD.

REFERENCES CITED The following references are of record in the file of this patent:

STATES PATENTS C016 May 12, 1942 

